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ESR prepress abstract   -  DOI: https://doi.org/10.3354/esr01303

Factors driving incubation temperatures and the effects of long-term exposure to thermal stress on Eretmochelys imbricata eggs in St. Croix, USVI

Erin Lyons*, Evan D’Alessandro, Manoj Shivlani, Clayton Pollock, Kristen Ewen

*Corresponding author:

ABSTRACT: The hawksbill sea turtle is listed as Critically Endangered under the IUCN and has been slow to recover in the Caribbean due to historical exploitation and ongoing anthropogenic threats. In turtles, sex and reproductive success are determined by incubation temperatures, whereby lower temperatures produce male hatchlings and higher temperatures produce female hatchlings. As incubation temperatures increase due to climate change, nests are predicted to produce predominantly female hatchlings, threatening sex ratios, reproductive success, and species persistence. One of the largest remaining nesting hawksbill populations within the USA nests on Buck Island. This study aims to (1) assess the factors driving incubation temperatures and (2) identify the relationship between hatch success and the proportion of time exposed to increasing incubation temperatures. Nest incubation temperatures, beach sector, habitat type, deposition month, percent soil composition, hatch success, and emergence success data were collected from 2019 to 2021. Differences in incubation temperatures across these factors confirms that the absence of vegetative cover is increasing incubation temperatures on Buck Island, leading to reduced hatchling survival. Results from this study indicate that declines in hatch success may be driven by long-term exposure to temperatures that were previously considered non-lethal to embryos in the literature. These findings emphasize the continued need for conservation interventions to protect the future of hawksbills.